Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D65/00—Parts or details
  • F16D65/02—Braking members; Mounting thereof
  • F16D65/12—Discs; Drums for disc brakes
  • F16D65/125—Discs; Drums for disc brakes characterised by the material used for the disc body
  • F16D65/126—Discs; Drums for disc brakes characterised by the material used for the disc body the material being of low mechanical strength, e.g. carbon, beryllium; Torque transmitting members therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D13/00—Friction clutches
  • F16D13/58—Details
  • F16D13/60—Clutching elements
  • F16D13/64—Clutch-plates; Clutch-lamellae
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
  • F16D69/04—Attachment of linings
  • F16D69/0408—Attachment of linings specially adapted for plane linings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
  • F16D69/04—Attachment of linings
  • F16D2069/0425—Attachment methods or devices
  • F16D2069/0433—Connecting elements not integral with the braking member, e.g. bolts, rivets
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D65/00—Parts or details
  • F16D65/02—Braking members; Mounting thereof
  • F16D65/12—Discs; Drums for disc brakes
  • F16D65/121—Discs; Drums for disc brakes consisting of at least three circumferentially arranged segments

Definitions

• This invention relates to a method of constructing a carbon composite laminated structure in the form of a friction disc of the kind comprising a layer of carbon composite material, such as a carbon-carbon composite material, and to a laminated structure resulting from the method. It relates in particular, though not exclusively, to a method of manufacture of a laminated structure for use at high temperatures, such as those experienced by the carbon-carbon composite rotor and stator friction discs of an aircraft brake assembly.
• Friction discs of carbon composite material are extremely expensive to produce. Thus as well as seeking to maximise the wear life of such discs, strenuous efforts inevitably have been made to ensure that the maximum possible benefit is derived even from the material of fully worn discs.
• brazing technique is found to work well and the resulting refurbished discs exhibit good performance in use.
• the brazing technique is notable for requiring the use of specialised equipment. Despite this limitation, no viable alternatives have been proposed so far concerning any alternative and potentially more convenient techniques for refurbishing friction discs.
• the subject invention seeks to provide an improved laminated structure in the form of a friction disc and method of constructing a laminated structure of a kind comprising a layer of carbon composite material.
• a method of constructing a laminated friction disc of a kind comprising a layer of carbon composite material which provides a wear surface comprises arranging said layer of carbon composite material against a second layer of material with said wear surface facing away from said second layer of material, forming holes in each of said layers either before or after arranging said layers against one another with the holes in the layer of carbon composite material extending through said wear surface and with the holes in said second layer aligned with the holes in the layer of carbon composite material, positioning fastening means to extend through aligned pairs of holes and arranging said fastening means to secure said layers one against the other with each said fastening means lying wholly below and spaced from at least the wear surface of the layer of carbon composite material.
• the fastening means lie spaced wholly below said wear surface by a distance greater than the wear allowance of the disc.
• the fastening means is below the wear surface at all times in subsequent normal use.
• the invention further provides a method for increasing the effective thickness of a layer of carbon composite material of a friction disc by utilising for the second layer a layer which is also of carbon composite material.
• More than two layers may be laminated together, in which case individual fastening means may extend through either all or only fewer than all the layers. Some fastening means may serve to connect together some of a plurality of layers and other fastening means may act between one or some of those layers and the other layers of the plurality.
• the invention may be employed to laminate together two layers of corresponding shape and size in a manner in which confronting surfaces of the layers are wholly in contact with one another.
• it may be employed to laminate two components of different shape and size in a manner in which the confronting surfaces of the two components are not wholly in contact.
• a layer of an annular shape such as that of a brake friction disc, may be formed by assembling together a plurality of segments into an annular form and overlaying with a second plurality of segments in a manner in which the segments in the second layer are offset circumferentially from those in the first layer.
• the layer of carbon composite material and the second layer, whether or not of carbon composite material, may be of equal thickness or one may be thicker than the other.
• a layer of a material other than carbon-carbon composite material may be sandwiched as a core layer between two layers of carbon-carbon material. Any such core layer may be of a strength substantially only sufficient to withstand the torque loads transmitted thereto by the fastening means.
• the invention further provides a laminated friction disc comprising a layer of carbon composite material which provides a wear surface and a second layer of material held against a surface of the layer of carbon composite material opposite said wear surface by fastening means which, as viewed in a direction perpendicular to the wear surface, lies within the area of said wear surface at a position wholly below said surface.
• the fastening means shall be of a material which does not readily form a carbide, for example a metal for which the free energy of formation of carbides is positive, and including an alloy of any such metal.
• Suitable materials include nickel or cobalt, alloys thereof and nickel based or cobalt based alloys such as Nimonic, e g Nimonic 75. These materials have a good ability to withstand high temperatures and thermal shock loads.
• Other suitable materials for withstanding a high temperature include ceramics though the resistance of many ceramics to thermal shock is not high.
• Preferred ceramic materials include silicon carbide and carbon-carbon. These have a favourable combination of mechanical and physical properties for thermal shock resistance.
• the fastening means may be in the form of a dowel pin, i e of simple cylindrical shape, and secured in position by means of adhesives and/or by virtue of surface texturing of the cylindrical surface.
• Suitable adhesives include phenolic resins which are subsequently charred by heating to a high temperature.
• Suitable surface texturing includes longitudinally extending ribs (i e spline-like formations) and circumferentially extending formations such as annular barb-like ribs.
• the fastening means may be comprised by for example a dowel pin, more preferably it is in the form of a rivet, for example, a hollow or a solid type rivet.
• the outer surface i e wear surface of the carbon composite layer may be recessed in the vicinity of the holes thereby to accommodate the rivet head or deformed rivet tail in a manner in which it lies below the wear surface of the carbon composite layer.
• a particularly suitable type of rivet is considered to be one of the kind which is solid in cross-section in the vicinity of its head portion and hollow in cross-section in the vicinity of its tail portion. It is further preferred that the rivet is not of the conventional kind having a uniform cylindrically shaped external surface, but is one having a waisted external shape around a substantial proportion of the length of the hollow portion. Preferably the waisted portion is selected so as to lie, when the rivet is in situ in the holes of the layers, and prior to deformation of its tail portion, such that the waisted portion is aligned axially with that surface against which the tail portion is to be deformed. The risk of damage to material of the layer against which the tail portion is deformed, particularly when of carbon composite material, is believed thereby to be significantly reduced.
• fastening means having a head and/or a tail portion between which the layers of the laminated friction disc are secured said head and/or tail portions may be arranged to act on the layers- substantially only in direct compression.
• load distribution means such as an annular washer be provided so that a head or tail portion does not directly make contact with a confronting load bearing surface of one of the layers of the laminated friction disc.
• Suitable materials for the load bearing means include nickel, cobalt and alloys comprising one or both of these materials.
• the l ⁇ ad distribution means and the fastening means are of the same material.
• the load distribution means may have a planar surface for contact with a layer of carbon composite material or it may have a non-planar, e g a fru ⁇ to-conically shaped surface for confronting a rivet tail or a rivet head of the countersunk type.
• the fastening means are provided within a band covering the middle 80% of the radial width of an annular wear area.
• fastening means lie at a radius at least that of the average of the radii of the inner and outer boundaries of the annular wear area of the friction disc. More preferably fastening means lie at a position which is outwards of said inner diameter by at least 50 but less than 75% of the difference between said inner and outer diameters.
• the friction disc may be of an asymmetric configuration in which the layer of carbon composite material is of a thickness different from that of said second layer.
• the layers may be 45 and 55% respectively of the total thickness.
• the invention is believed to be particularly useful in the use of one or more layers of carbon composite material which are of carbon-carbon composite material.
• Figure 1 is a face view of part of a carbon- carbon composite brake friction disc in accordance with the present invention
• Figure 2 is a section on the line 2-2 of Figure 1 and prior to deformation of the rivets
• Figure 3 is a longitudinal sectional view of a rivet for use in a brake disc of Figures 1 and 2
• Figure 4 shows the rivet of Figure 3 when in situ and deformed
• Figures 5 and 6 are cross-sectional views corresponding to that of Figure 2 of two other embodiments of the present invention.
• a laminated carbon-carbon composite brake rotor disc 10 comprises two annular layers 11,12 of carbon- carbon composite material each formed from worn brake discs which have been machined as necessary to 50% of the thickness of the brake to be constructed by the method of this invention.
• the disc 10 is a rotor disc having outer key formations of conventional kind though it will be appreciated that the invention is equally applicable to stators.
• the two layers 11,12 are secured together in a manner that resists their separation and relative rotation by means of eight fastening means in the form of rivets 15.
• the rivets 15 are located in respective holes 16 uniformly circumferentially spaced about the disc on a pitch circle radius 17 which equals that of the inner boundary 13 plus two-thirds of the difference between the inner and outer boundaries 13,14.
• Each rivet 15, prior to deformation has the shape shown in Figure 3. Notably it comprises a flat countersunk type head portion 18, a solid cross-section stem portion 19 of cylindrical shape and a hollow cross-section tail portion 20.
• the tail portion has a waisted external profile comprising a waist region 19 which extends over approximately 75% of the axial length of the hollow tail portion. Over the remaining 25% of its axial length, and being at the distal end of the hollow portion, the external surface 22 is of a cylindrical shape and corresponds in diameter with that of the stem portion 19.
• the holes 16 in the layers 11,12 are each formed at the exposed surfaces 23,24 of the disc with recesses 25,26.
• the bases 27 of the recesses are frusto-conically shaped.
• the axial dimension of each rivet 15 is selected such that when it is arranged to lie in a pair of aligned holes 16 with the discs 11,12 clamped together for rivetting, the waist portion 21 is axially aligned (and extends axially to each side of) the radially inner edge 28 of the frustoconical shaped surface 27.
• rivets of the aforementioned shape as shown in Figure 3.
• solid or completely hollow type rivets may be used.
• FIGs 5 and 6 show rivets 50,60 which have been deformed to hold together two adjacent machined layers of carbon composite material. Because these rivets do not possess waisted end regions use is made of washers 51,61 to distribute load transmitted between the ends of the rivets and the layers.
• the washers each have planar surfaces 52,62 for bearing against planar annular end faces of the recesses 53,63.
• FIG. 5 shows a rivet 50 having a flat countersunk head and Figure 6 shows a rivet 60 having a round head.
• a washer 54 has a countersunk region 55 for abutment by the countersunk type head of the rivet.
• the washer 54 thus corresponds with washer 51.
• rivet 60 has a round head with a planar annular rear face 64.
• the head washer 65 is thus of a simple flat disc type and corresponds with washer 61.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Braking Arrangements (AREA)
• Mechanical Operated Clutches (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10660494

Family Applications (1)

Country Status (6)

Families Citing this family (43)

Family Cites Families (28)

• 1989
  • 1989-07-22 GB GB8916822A patent/GB2234024B/en not_active Expired - Fee Related
• 1990
  • 1990-07-19 JP JP2510340A patent/JPH05500409A/ja active Pending
  • 1990-07-19 AU AU60370/90A patent/AU6037090A/en not_active Abandoned
  • 1990-07-19 US US07/807,832 patent/US5299667A/en not_active Expired - Fee Related
  • 1990-07-19 EP EP90910800A patent/EP0484366A1/de not_active Ceased
  • 1990-07-19 WO PCT/GB1990/001113 patent/WO1991001456A1/en not_active Ceased

Non-Patent Citations (1)

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